The present invention relates to a cap for closing the mouth of a filler neck, and in particular to fuel caps for closing the filler neck of a vehicle fuel tank. More particularly, the present invention relates to a cap including an attachment mechanism for enabling a user to attach the cap to the filler neck quickly and easily and establish a sealed connection between the cap and the filler neck.
Conventional fuel caps for closing the filler neck of a vehicle fuel tank typically include a closure member for closing the mouth of the filler neck and a handle for turning the closure member to mount the closure member in the filler neck. Partial turn cam-on caps and multiple turn threaded caps are well-known types of caps for use in closing filler necks. Although such caps are currently in widespread use, it would be desirable to provide an alternative cap that is simpler to install on and remove from a filler neck.
It is known to provide a cam-on cap of the type having a shank portion which extends into the filler neck and is provided with pairs of conventional circumferentially spaced-apart cam lugs as disclosed in U.S. Pat. No. 4,887,733 to Harris. These cam lugs operate in the customary way to engage a filler neck configured to receive a cam-on cap and retain the cap in a fully tightened position closing the open mouth of the filler neck.
Alternatively, a conventional multiple turn cap includes a closure member that is threaded to be screwed into a threaded filler neck. For example, U.S. Pat. No. 3,820,680 to Friend discloses a multiple turn threaded cap and a compatible threaded filler neck. Typically, a multiple turn threaded cap must be turned at least two and one-half or three full revolutions by the user after it is inserted into the threaded filler neck to connect the cap to the filler neck and establish a liquid and vapor seal between the cap and the filler neck.
More and more vehicle drivers are using the self-service bays at gasoline stations and filling their own fuel tanks. Some people have found that it is difficult to remove and install a conventional filler neck cap during refueling. A cap that is readily installable on and removable from a filler neck by a user without a lot of effort and that is configured to establish a sturdy sealed connection between the cap and the filler neck consistently during use would be a welcomed improvement over conventional caps.
According to the present invention, a quick-on cap is provided for engaging a filler neck. The cap includes means for closing the mouth of the filler neck and means for gripping the filler neck to establish a fuel vapor seal between the closing means and the filler neck. The closing means includes a core and a sleeve that is movable relative to the core. The sleeve carries a sealing ring that is configured to seal against the filler neck. The gripping means is coupled to the core and sleeve and grips the filler neck to compress the sealing ring between the sleeve and the filler neck in response to movement of the core relative to the sleeve in a cap-installation direction.
In preferred embodiments, the closing means further includes a handle cover coupled to the core to make it easy for a user to move the core relative to the sleeve in the cap-installation direction an amount sufficient to actuate the gripping means. Illustratively, the sleeve is a tubular member that is formed to include a passageway extending therethrough and containing the cylindrical core and the core is rotated a fraction of a turn relative to the sleeve to actuate the gripping means.
In use, the cap is inserted into the filler neck so that axially extending anti-rotation ribs provided on the exterior wall of the sleeve engage internal flanges or abutments provided in the filler neck to block rotation of the sleeve inside the filler neck during installation of the cap. A user then turns the exterior handle cover a small amount (e.g., one-eighth of a turn) to rotate the core inside the sleeve and cause a retaining lug appended to the core to slip into a slot and engage another internal flange or abutments provided in the filler neck. Removal of the cap from the filler neck is now blocked by engagement of the retaining lug and the internal flange. At the same time, a spring and cam mechanism coupled to the core and sleeve operate automatically to convert rotation of the handle cover and core into axial movement of the sleeve and urge the non-rotatable sleeve further in an axially inward direction into the filler neck. This axial movement of the sleeve into the filler neck advantageously causes the sealing ring carried on the sleeve to be compressed between the sleeve and the filler neck so that a fuel vapor seal is established between the closing means and the filler neck.
Thus, in preferred embodiments, the gripping means comprises means for engaging the filler neck disposed on the sleeve to prevent rotation of the sleeve in the filler neck and to permit axial movement of the sleeve in the filler neck, means for engaging the filler neck to prevent axial outward movement of the cap from the filler neck when the core is rotated in the cap-installation direction, spring means for yieldably urging the sleeve axially inwardly in response to rotational movement of the core in the cap-installation direction, and control means for releasing the spring means in response to such movement in the cap-installation direction and for loading said spring means in response to rotational movement in the opposite direction.
In accordance with the present invention, the preferred filler neck is provided with a gripping portion disposed axially inwardly from the mouth of the filler neck and located inside the filler neck. This gripping portion may include radially inwardly extending abutments or flanges to be engaged by engaging means carried, respectively, on the sleeve and the core.
Illustratively, the core may be a tubular member containing a pressure-relief valve and a vacuum-relief valve. The pressure-relief valve operates to vent excess fuel vapor pressure in the filler neck to the atmosphere when the cap is installed on the filler neck. The vacuum-relief valve operates to introduce air from the atmosphere into the filler neck whenever the cap is in place on the filler neck and the pressure in the filler neck falls a predetermined amount below atmospheric pressure. The sleeve surrounds the tubular member and is coaxially aligned with the longitudinal axis of rotation of the tubular member. A second sealing ring is provided around the tubular member and inside the sleeve to establish a fuel vapor seal between the core and the sleeve yet allow rotation of the core relative to the sleeve during installation and removal of the filler neck cap.
In a preferred embodiment, the spring and cam mechanism that is responsible for establishing the fuel vapor seal between the closing means and the filler neck includes a cam on the core, a cam follower on the sleeve, and a spring acting against the core and the sleeve to urge the cam follower into engagement with the cam. Illustratively, the spring is a cylindrical compression spring that is arranged around the tubular core and positioned to lie in the cylindrical space between the exterior of the tubular core and the interior of the surrounding cylindrical sleeve.
The spring urges the core and sleeve in opposite directions. Thus, the spring tends to urge the core in an axially outward direction to wedge the retaining lug on the core against the internal flange on the filler neck so that the core is effectively anchored to the filler neck. Also, the spring tends to push against the anchored core to urge the sleeve in an axially inward direction to compress the sealing ring carried by the sleeve between the sleeve and the filler neck.
The importance of the cam mechanism as a control means is that it acts to hold the spring in a compressed position until after the cap is inserted into the filler neck to engage the sleeve ribs and certain internal flanges in the filler neck so that the sleeve is unable to rotate within the filler neck and the handle cover is moved (e.g., rotated one-eighth of a turn) relative to the filler neck so that the core is rotated relative to the sleeve. During such movement of the core relative to the sleeve, the cam mechanism operates to "release" the spring so that it can expand and move the non-rotatable sleeve further in the axially inward direction into the filler neck. Thus, the spring urges the sleeve inwardly to compress the sealing ring between the sleeve and the filler neck so that a fuel vapor seal is established between the closing means and the filler neck. Conversely, the control means or cam mechanism preferably serves to load the spring when the core is rotated relative to the sleeve in a cap-removal direction.
During installation and removal of the quick-on filler neck cap, it is only necessary for the user to move the handle cover of the cap a small amount relative to the filler neck to tighten or loosen the cap during refueling. The spring acting on the cam follower and cam also urges the gripping means toward the fully installed position resulting in a predetermined amount of self-actuation in the installation direction. Advantageously, the gripping means included in the quick-on filler neck cap acts automatically using the spring and cam mechanism to establish a tight fuel vapor seal between the cap and filler neck during cap installation and minimize the chances that such a seal will not be established as a result of improper installation of the cap. Also, users will appreciate the fact that it is simpler to install and remove the quick-on filler neck cap than conventional partial turn cam-on and multiple turn threaded caps. An additional advantage is that the sealing ring between the cap and the filler neck is less likely to be scuffed during installation of the cap on the filler neck because it is moved axially against the filler neck instead of being rotated into engagement with the filler neck.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.